import java.util.Scanner;
import java.util.Date;
class Date{
    public int year;
    public int month;
    public int day;
    //static修饰的方法中不能访问任何非静态变量
    //this是为了避免重名时堆区的变量赋值失败
    //如果privite修饰方法就不能在不同类中引用
    public void  SetData(int year, int month, int day){
        this.day=day;
        this.month=month;
        this.year=year;
    }
    public void ShowData()
    {
        System.out.println("year:"+year+" month:"+month+" day:"+day);
    }
    public Date(int year,int month,int day){
        this.year=year;
        this.month=month;
        this.day=day;
    }
}

public class Main {

    public static void main(String[] args) {
        double x=0.0;
        double y=0.0;
        Scanner scanner=new Scanner(System.in);
        double ret=0.0;
        ret=Math.pow(x,2)+
    }

}


